Switch to a 50mm f/1.4 prime lens and the largest available aperture is four stops faster. In low light you'd be limited to a shutter speed of, say, 1/15 sec with a typical zoom (unless you increase your ISO setting). However, an f/1.4 lens will enable a much faster shutter speed of 1/250 sec.
Influenza, commonly known as the flu, is an infectious disease caused by an influenza virus. Symptoms can be mild to severe. The most common symptoms include: a high fever, runny nose, sore throat, muscle pains, headache, coughing, and feeling tired. These symptoms typically begin two days after exposure to the virus and most last less than a week. The cough, however, may last for more than two weeks. In children, there may be nausea and vomiting, but these are not common in adults. Nausea and
You are correct in that it is difficult to find an answer to your question on the Web. I was trying to find a good link for you, but found none. Here is a basic summary of what causes the symptoms encountered during the flu. Common flu symptoms include fever, sore throat, muscle aches, shivers and cold sweats, etc. These symptoms are not caused by the virus itself but rather by our bodies' response to the the virus. The immune system mounts a two-fold response to the virus.